Pelvic attachment for artificial legs



June 11, 1935, G. DORSCH PELVIC ATTACHMENT FOR ARTIFICIAL LEGS I Filed Aug. 17, 1935' Patented June 11, 1935 UNITED STATES PELVIC ATTACHMENT FOR LEGS an'rmrcmr.

George Dorsch, New York, N. Y. Application August 17, 1933, Serial No. 685,540

4 Claims.

This invention relates to artificial legs, and more especially to a pelvic belt attachment therefor.

The object of the invention is to provide a simple, compact and reliable joint connection between the belt and the upper or thigh section of an artificial leg whereby the movements of the limb in and to any of a variety of. 'simulative natural positions can be efficiently accomplished with ease and confidence by the user.

To this end my invention embodies a link and rocker device of novel construction and operation connecting the belt and the upper section of the leg in such manner that the belt is maintained in substantially the same position around the pelvic zone, irrespective of the various movements of the limb or the body of the wearer, which device in an efiicient form of the invention will be hereinafter described, and the scope of the invention then expressed in the appended claims.

In the drawing- V Figure 1 is an elevation of the attachment as in use, showing the relative positions of .the belt, link and rocker members when theuser is in standing posture, and also indicating in dotted lines the positions of such members when the limb is raised as in sitting.

Fig. 2 illustrates the relative positions of the 30 said members when the user is in a sitting posture on the floor with his knee raised.

Fig. 3 illustrates the relative positions of the said members when the body of the user is bent forward as in a kneeling or creeping posture.

er thereon, and the adjacent pivoted ends of the links.

Fig. 5 is a transverse vertical section, as on the line 5-5 of Fig. 4.

Referring to the drawing, A designates the upper or thigh section of an artificial leg as in use; B designates the pelvic belt, and C designates the joint connection between the belt and the outer side of the adjacent section of the leg in which the usual stump-receiving socket is formed.

In the preferred embodiment of the invention herein illustrated this connection comprises aplate 6 riveted or otherwise firmly secured to one side of the belt, as at I, so as to constitute, in eflect, a part ofthe belt; a plate 8 riveted or otherwise secured to the outer side of the upper leg section, 'as at 9; a rocker comprising a lever plate In centrally pivoted to the leg plate, as at H, in close relation to the region of the tro- Fig. 4 is an elevation of the leg plate, the rockment as distinguished from a movement in the .10

reverse direction were the rocker above the chanter joint.

The front link I! is ofiset from its lower pivotal connection, as at I6, and is therefore shorter than the back link l3. The lower axes i5 of the 15 two links when the links are in vertical position or substantially-so are equally spaced at the respective sides of and slightly below the axis of the then horizontally-disposed lever plate Ill, and the upper pivotal point It on the belt plate 20 of the rearward longer link 13 is somewhat above the adjacentpivotal point of the forward link I2.

Preferably an anti-friction bearing of substantial area for the rocker is provided; which bearing in the present instance comprises balls I! seated 25 in complementary annular grooves or races 8 and is formed in the leg and lever plates respectively.

tro-

The pivot pin i I preferably comprises a polygonal portion 20 which is seated in corresponding apertures in the wall of the leg section and in the plate 8; a cylindrical portion 2| upon which the lever plate is centrally fulcrumed, and a threaded portion 22 having a securing nut 23 for the lever plate.

24 designates the'usual elastic control strap connecting the pelvic belt and the lower pivoted section 25 of the artificial limb.

By the foregoing described construction it will be apparent that the limb is always kept close to the body and can not be pulled. therefrom, thus 40 inspiring confidence in the user; and that there is provided between the artificial limb and the pelvic belt an efiicient joint connection which is readily responsive to the various movements of the stump of the thigh without objectionable effort or discomfort and which connection permits free bodily movements of the wearer. Forexample, as illustrated in Fig. l, correctness ofnormal standing posture is ensured by virtue of the upright parallel a relation of the links at the respective sides of the axis of the horizontally-disposed lever plate, and as indicated in this figure in dotted lines the limb by a natural movement of the associated thigh of the user can be swung forward, as in sitting 56 with perfect knee control by reason of the simultaneous angular and rotative movements of the pivotal link and rocker connection in co-operative relation to the movements of the limb without in any case any substantial shifting of the belt from its original position relative to the pelvic zone of the wearers body. That is to say, in the forward movement of the leg the rocker is forwardly swung therewith and at the same time by virtue of the relatively. long and short link connections is freely movable about its axis I l to accommodate the curved movements of the lower pivotally connected ends of the forwardly swinging links without binding stress or strain of the links between the rocker and the belt. -In other words, the two links swing as a pendulum from their respective pivots l4, while the rocker is moved about its axis in accordance with the curved paths described by the lower ends of the links. In the backward movement of the leg and also during the various movements of the body in relation to the leg, the axis of the rocker is moved with and in the same direction as the leg and the uniform fiexible quality of the joint connection is maintained.

By virtue of the curved lower portion of the forward link l2, provision is had for an extended rotative movement of the rocker in the forward swinging motion of the leg, before the link abuts pivoted component parts of the joint connection without any substantial displacement of the belt permit a. natural sitting posture of the user, and as seen in Fig. 3 the relative movements of such parts without any substantial belt displacement permit a natural kneeling or creeping position of the user. a

It is to be understood that my invention is not limited to the details of construction herein disclosed as the device may be variously modified within the principle of the invention and the scope of the appended claims.

. I claiml. The combination with a pelvic belt and an artificial leg, of a. rocker mounted on the outer side of the upper leg section, and front and back links pivotally connecting said rocker to the belt and of a length to cause the rocker to move with the leg when worn, said links having their axes on the rocker beyond the respective sides of the rocker axis, and the front link being shorter than the back link, whereby the rocker is oscillated during the movement of the leg.

2. The combination with a pelvic belt and an artificial leg, of a rocker mounted on the outer side of the upper leg section, and front and back links pivotally connecting said rocker to the belt andof a length to cause the rocker to move with the leg when worn, said links having their axes on the rocker beyond the respective sides of the rocker axis, and the front link being shorter than the back link, whereby the rocker is oscillated during the movement of the leg, said link having a forward offset adjacent its pivotal connection to the rocker.

3. The combination with a pelvic belt and an artificial leg having a stump-receiving socket in the thigh section thereof, of a rocker mounted to oscillate on the outer side of the said thigh section, and front and back links pivotally connected to said rocker and to the belt and of a length to cause the rocker to move with the leg when worn, said links having their axes on the rocker beyond the respective sides of the rocker axis, the axis on the belt of the forward link being below that of the rearward link on the belt, whereby during the motions of the leg by the wearer the rocker is swung in the same direction as the leg and at the same time is worn, said links having their axes on the rocker beyond the respective sides of and on a line below the rocker axis and one of said links being shorter than the other.

GEORGE DORSCH. 

